xref: /freebsd/sys/kern/sys_generic.c (revision 396c556d77189a5c474d35cec6f44a762e310b7d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)sys_generic.c	8.5 (Berkeley) 1/21/94
37  */
38 
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 #include "opt_capsicum.h"
43 #include "opt_compat.h"
44 #include "opt_ktrace.h"
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/sysproto.h>
49 #include <sys/capsicum.h>
50 #include <sys/filedesc.h>
51 #include <sys/filio.h>
52 #include <sys/fcntl.h>
53 #include <sys/file.h>
54 #include <sys/lock.h>
55 #include <sys/proc.h>
56 #include <sys/signalvar.h>
57 #include <sys/socketvar.h>
58 #include <sys/uio.h>
59 #include <sys/kernel.h>
60 #include <sys/ktr.h>
61 #include <sys/limits.h>
62 #include <sys/malloc.h>
63 #include <sys/poll.h>
64 #include <sys/resourcevar.h>
65 #include <sys/selinfo.h>
66 #include <sys/sleepqueue.h>
67 #include <sys/syscallsubr.h>
68 #include <sys/sysctl.h>
69 #include <sys/sysent.h>
70 #include <sys/vnode.h>
71 #include <sys/bio.h>
72 #include <sys/buf.h>
73 #include <sys/condvar.h>
74 #ifdef KTRACE
75 #include <sys/ktrace.h>
76 #endif
77 
78 #include <security/audit/audit.h>
79 
80 /*
81  * The following macro defines how many bytes will be allocated from
82  * the stack instead of memory allocated when passing the IOCTL data
83  * structures from userspace and to the kernel. Some IOCTLs having
84  * small data structures are used very frequently and this small
85  * buffer on the stack gives a significant speedup improvement for
86  * those requests. The value of this define should be greater or equal
87  * to 64 bytes and should also be power of two. The data structure is
88  * currently hard-aligned to a 8-byte boundary on the stack. This
89  * should currently be sufficient for all supported platforms.
90  */
91 #define	SYS_IOCTL_SMALL_SIZE	128	/* bytes */
92 #define	SYS_IOCTL_SMALL_ALIGN	8	/* bytes */
93 
94 #ifdef __LP64__
95 static int iosize_max_clamp = 0;
96 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
97     &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
98 static int devfs_iosize_max_clamp = 1;
99 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW,
100     &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices");
101 #endif
102 
103 /*
104  * Assert that the return value of read(2) and write(2) syscalls fits
105  * into a register.  If not, an architecture will need to provide the
106  * usermode wrappers to reconstruct the result.
107  */
108 CTASSERT(sizeof(register_t) >= sizeof(size_t));
109 
110 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
111 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
112 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
113 
114 static int	pollout(struct thread *, struct pollfd *, struct pollfd *,
115 		    u_int);
116 static int	pollscan(struct thread *, struct pollfd *, u_int);
117 static int	pollrescan(struct thread *);
118 static int	selscan(struct thread *, fd_mask **, fd_mask **, int);
119 static int	selrescan(struct thread *, fd_mask **, fd_mask **);
120 static void	selfdalloc(struct thread *, void *);
121 static void	selfdfree(struct seltd *, struct selfd *);
122 static int	dofileread(struct thread *, int, struct file *, struct uio *,
123 		    off_t, int);
124 static int	dofilewrite(struct thread *, int, struct file *, struct uio *,
125 		    off_t, int);
126 static void	doselwakeup(struct selinfo *, int);
127 static void	seltdinit(struct thread *);
128 static int	seltdwait(struct thread *, sbintime_t, sbintime_t);
129 static void	seltdclear(struct thread *);
130 
131 /*
132  * One seltd per-thread allocated on demand as needed.
133  *
134  *	t - protected by st_mtx
135  * 	k - Only accessed by curthread or read-only
136  */
137 struct seltd {
138 	STAILQ_HEAD(, selfd)	st_selq;	/* (k) List of selfds. */
139 	struct selfd		*st_free1;	/* (k) free fd for read set. */
140 	struct selfd		*st_free2;	/* (k) free fd for write set. */
141 	struct mtx		st_mtx;		/* Protects struct seltd */
142 	struct cv		st_wait;	/* (t) Wait channel. */
143 	int			st_flags;	/* (t) SELTD_ flags. */
144 };
145 
146 #define	SELTD_PENDING	0x0001			/* We have pending events. */
147 #define	SELTD_RESCAN	0x0002			/* Doing a rescan. */
148 
149 /*
150  * One selfd allocated per-thread per-file-descriptor.
151  *	f - protected by sf_mtx
152  */
153 struct selfd {
154 	STAILQ_ENTRY(selfd)	sf_link;	/* (k) fds owned by this td. */
155 	TAILQ_ENTRY(selfd)	sf_threads;	/* (f) fds on this selinfo. */
156 	struct selinfo		*sf_si;		/* (f) selinfo when linked. */
157 	struct mtx		*sf_mtx;	/* Pointer to selinfo mtx. */
158 	struct seltd		*sf_td;		/* (k) owning seltd. */
159 	void			*sf_cookie;	/* (k) fd or pollfd. */
160 	u_int			sf_refs;
161 };
162 
163 static uma_zone_t selfd_zone;
164 static struct mtx_pool *mtxpool_select;
165 
166 #ifdef __LP64__
167 size_t
168 devfs_iosize_max(void)
169 {
170 
171 	return (devfs_iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
172 	    INT_MAX : SSIZE_MAX);
173 }
174 
175 size_t
176 iosize_max(void)
177 {
178 
179 	return (iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
180 	    INT_MAX : SSIZE_MAX);
181 }
182 #endif
183 
184 #ifndef _SYS_SYSPROTO_H_
185 struct read_args {
186 	int	fd;
187 	void	*buf;
188 	size_t	nbyte;
189 };
190 #endif
191 int
192 sys_read(td, uap)
193 	struct thread *td;
194 	struct read_args *uap;
195 {
196 	struct uio auio;
197 	struct iovec aiov;
198 	int error;
199 
200 	if (uap->nbyte > IOSIZE_MAX)
201 		return (EINVAL);
202 	aiov.iov_base = uap->buf;
203 	aiov.iov_len = uap->nbyte;
204 	auio.uio_iov = &aiov;
205 	auio.uio_iovcnt = 1;
206 	auio.uio_resid = uap->nbyte;
207 	auio.uio_segflg = UIO_USERSPACE;
208 	error = kern_readv(td, uap->fd, &auio);
209 	return(error);
210 }
211 
212 /*
213  * Positioned read system call
214  */
215 #ifndef _SYS_SYSPROTO_H_
216 struct pread_args {
217 	int	fd;
218 	void	*buf;
219 	size_t	nbyte;
220 	int	pad;
221 	off_t	offset;
222 };
223 #endif
224 int
225 sys_pread(struct thread *td, struct pread_args *uap)
226 {
227 
228 	return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
229 }
230 
231 int
232 kern_pread(struct thread *td, int fd, void *buf, size_t nbyte, off_t offset)
233 {
234 	struct uio auio;
235 	struct iovec aiov;
236 	int error;
237 
238 	if (nbyte > IOSIZE_MAX)
239 		return (EINVAL);
240 	aiov.iov_base = buf;
241 	aiov.iov_len = nbyte;
242 	auio.uio_iov = &aiov;
243 	auio.uio_iovcnt = 1;
244 	auio.uio_resid = nbyte;
245 	auio.uio_segflg = UIO_USERSPACE;
246 	error = kern_preadv(td, fd, &auio, offset);
247 	return (error);
248 }
249 
250 #if defined(COMPAT_FREEBSD6)
251 int
252 freebsd6_pread(struct thread *td, struct freebsd6_pread_args *uap)
253 {
254 
255 	return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
256 }
257 #endif
258 
259 /*
260  * Scatter read system call.
261  */
262 #ifndef _SYS_SYSPROTO_H_
263 struct readv_args {
264 	int	fd;
265 	struct	iovec *iovp;
266 	u_int	iovcnt;
267 };
268 #endif
269 int
270 sys_readv(struct thread *td, struct readv_args *uap)
271 {
272 	struct uio *auio;
273 	int error;
274 
275 	error = copyinuio(uap->iovp, uap->iovcnt, &auio);
276 	if (error)
277 		return (error);
278 	error = kern_readv(td, uap->fd, auio);
279 	free(auio, M_IOV);
280 	return (error);
281 }
282 
283 int
284 kern_readv(struct thread *td, int fd, struct uio *auio)
285 {
286 	struct file *fp;
287 	cap_rights_t rights;
288 	int error;
289 
290 	error = fget_read(td, fd, cap_rights_init(&rights, CAP_READ), &fp);
291 	if (error)
292 		return (error);
293 	error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
294 	fdrop(fp, td);
295 	return (error);
296 }
297 
298 /*
299  * Scatter positioned read system call.
300  */
301 #ifndef _SYS_SYSPROTO_H_
302 struct preadv_args {
303 	int	fd;
304 	struct	iovec *iovp;
305 	u_int	iovcnt;
306 	off_t	offset;
307 };
308 #endif
309 int
310 sys_preadv(struct thread *td, struct preadv_args *uap)
311 {
312 	struct uio *auio;
313 	int error;
314 
315 	error = copyinuio(uap->iovp, uap->iovcnt, &auio);
316 	if (error)
317 		return (error);
318 	error = kern_preadv(td, uap->fd, auio, uap->offset);
319 	free(auio, M_IOV);
320 	return (error);
321 }
322 
323 int
324 kern_preadv(td, fd, auio, offset)
325 	struct thread *td;
326 	int fd;
327 	struct uio *auio;
328 	off_t offset;
329 {
330 	struct file *fp;
331 	cap_rights_t rights;
332 	int error;
333 
334 	error = fget_read(td, fd, cap_rights_init(&rights, CAP_PREAD), &fp);
335 	if (error)
336 		return (error);
337 	if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
338 		error = ESPIPE;
339 	else if (offset < 0 &&
340 	    (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
341 		error = EINVAL;
342 	else
343 		error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
344 	fdrop(fp, td);
345 	return (error);
346 }
347 
348 /*
349  * Common code for readv and preadv that reads data in
350  * from a file using the passed in uio, offset, and flags.
351  */
352 static int
353 dofileread(td, fd, fp, auio, offset, flags)
354 	struct thread *td;
355 	int fd;
356 	struct file *fp;
357 	struct uio *auio;
358 	off_t offset;
359 	int flags;
360 {
361 	ssize_t cnt;
362 	int error;
363 #ifdef KTRACE
364 	struct uio *ktruio = NULL;
365 #endif
366 
367 	AUDIT_ARG_FD(fd);
368 
369 	/* Finish zero length reads right here */
370 	if (auio->uio_resid == 0) {
371 		td->td_retval[0] = 0;
372 		return(0);
373 	}
374 	auio->uio_rw = UIO_READ;
375 	auio->uio_offset = offset;
376 	auio->uio_td = td;
377 #ifdef KTRACE
378 	if (KTRPOINT(td, KTR_GENIO))
379 		ktruio = cloneuio(auio);
380 #endif
381 	cnt = auio->uio_resid;
382 	if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
383 		if (auio->uio_resid != cnt && (error == ERESTART ||
384 		    error == EINTR || error == EWOULDBLOCK))
385 			error = 0;
386 	}
387 	cnt -= auio->uio_resid;
388 #ifdef KTRACE
389 	if (ktruio != NULL) {
390 		ktruio->uio_resid = cnt;
391 		ktrgenio(fd, UIO_READ, ktruio, error);
392 	}
393 #endif
394 	td->td_retval[0] = cnt;
395 	return (error);
396 }
397 
398 #ifndef _SYS_SYSPROTO_H_
399 struct write_args {
400 	int	fd;
401 	const void *buf;
402 	size_t	nbyte;
403 };
404 #endif
405 int
406 sys_write(td, uap)
407 	struct thread *td;
408 	struct write_args *uap;
409 {
410 	struct uio auio;
411 	struct iovec aiov;
412 	int error;
413 
414 	if (uap->nbyte > IOSIZE_MAX)
415 		return (EINVAL);
416 	aiov.iov_base = (void *)(uintptr_t)uap->buf;
417 	aiov.iov_len = uap->nbyte;
418 	auio.uio_iov = &aiov;
419 	auio.uio_iovcnt = 1;
420 	auio.uio_resid = uap->nbyte;
421 	auio.uio_segflg = UIO_USERSPACE;
422 	error = kern_writev(td, uap->fd, &auio);
423 	return(error);
424 }
425 
426 /*
427  * Positioned write system call.
428  */
429 #ifndef _SYS_SYSPROTO_H_
430 struct pwrite_args {
431 	int	fd;
432 	const void *buf;
433 	size_t	nbyte;
434 	int	pad;
435 	off_t	offset;
436 };
437 #endif
438 int
439 sys_pwrite(struct thread *td, struct pwrite_args *uap)
440 {
441 
442 	return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
443 }
444 
445 int
446 kern_pwrite(struct thread *td, int fd, const void *buf, size_t nbyte,
447     off_t offset)
448 {
449 	struct uio auio;
450 	struct iovec aiov;
451 	int error;
452 
453 	if (nbyte > IOSIZE_MAX)
454 		return (EINVAL);
455 	aiov.iov_base = (void *)(uintptr_t)buf;
456 	aiov.iov_len = nbyte;
457 	auio.uio_iov = &aiov;
458 	auio.uio_iovcnt = 1;
459 	auio.uio_resid = nbyte;
460 	auio.uio_segflg = UIO_USERSPACE;
461 	error = kern_pwritev(td, fd, &auio, offset);
462 	return(error);
463 }
464 
465 #if defined(COMPAT_FREEBSD6)
466 int
467 freebsd6_pwrite(struct thread *td, struct freebsd6_pwrite_args *uap)
468 {
469 
470 	return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
471 }
472 #endif
473 
474 /*
475  * Gather write system call.
476  */
477 #ifndef _SYS_SYSPROTO_H_
478 struct writev_args {
479 	int	fd;
480 	struct	iovec *iovp;
481 	u_int	iovcnt;
482 };
483 #endif
484 int
485 sys_writev(struct thread *td, struct writev_args *uap)
486 {
487 	struct uio *auio;
488 	int error;
489 
490 	error = copyinuio(uap->iovp, uap->iovcnt, &auio);
491 	if (error)
492 		return (error);
493 	error = kern_writev(td, uap->fd, auio);
494 	free(auio, M_IOV);
495 	return (error);
496 }
497 
498 int
499 kern_writev(struct thread *td, int fd, struct uio *auio)
500 {
501 	struct file *fp;
502 	cap_rights_t rights;
503 	int error;
504 
505 	error = fget_write(td, fd, cap_rights_init(&rights, CAP_WRITE), &fp);
506 	if (error)
507 		return (error);
508 	error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
509 	fdrop(fp, td);
510 	return (error);
511 }
512 
513 /*
514  * Gather positioned write system call.
515  */
516 #ifndef _SYS_SYSPROTO_H_
517 struct pwritev_args {
518 	int	fd;
519 	struct	iovec *iovp;
520 	u_int	iovcnt;
521 	off_t	offset;
522 };
523 #endif
524 int
525 sys_pwritev(struct thread *td, struct pwritev_args *uap)
526 {
527 	struct uio *auio;
528 	int error;
529 
530 	error = copyinuio(uap->iovp, uap->iovcnt, &auio);
531 	if (error)
532 		return (error);
533 	error = kern_pwritev(td, uap->fd, auio, uap->offset);
534 	free(auio, M_IOV);
535 	return (error);
536 }
537 
538 int
539 kern_pwritev(td, fd, auio, offset)
540 	struct thread *td;
541 	struct uio *auio;
542 	int fd;
543 	off_t offset;
544 {
545 	struct file *fp;
546 	cap_rights_t rights;
547 	int error;
548 
549 	error = fget_write(td, fd, cap_rights_init(&rights, CAP_PWRITE), &fp);
550 	if (error)
551 		return (error);
552 	if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
553 		error = ESPIPE;
554 	else if (offset < 0 &&
555 	    (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
556 		error = EINVAL;
557 	else
558 		error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
559 	fdrop(fp, td);
560 	return (error);
561 }
562 
563 /*
564  * Common code for writev and pwritev that writes data to
565  * a file using the passed in uio, offset, and flags.
566  */
567 static int
568 dofilewrite(td, fd, fp, auio, offset, flags)
569 	struct thread *td;
570 	int fd;
571 	struct file *fp;
572 	struct uio *auio;
573 	off_t offset;
574 	int flags;
575 {
576 	ssize_t cnt;
577 	int error;
578 #ifdef KTRACE
579 	struct uio *ktruio = NULL;
580 #endif
581 
582 	AUDIT_ARG_FD(fd);
583 	auio->uio_rw = UIO_WRITE;
584 	auio->uio_td = td;
585 	auio->uio_offset = offset;
586 #ifdef KTRACE
587 	if (KTRPOINT(td, KTR_GENIO))
588 		ktruio = cloneuio(auio);
589 #endif
590 	cnt = auio->uio_resid;
591 	if (fp->f_type == DTYPE_VNODE &&
592 	    (fp->f_vnread_flags & FDEVFS_VNODE) == 0)
593 		bwillwrite();
594 	if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
595 		if (auio->uio_resid != cnt && (error == ERESTART ||
596 		    error == EINTR || error == EWOULDBLOCK))
597 			error = 0;
598 		/* Socket layer is responsible for issuing SIGPIPE. */
599 		if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
600 			PROC_LOCK(td->td_proc);
601 			tdsignal(td, SIGPIPE);
602 			PROC_UNLOCK(td->td_proc);
603 		}
604 	}
605 	cnt -= auio->uio_resid;
606 #ifdef KTRACE
607 	if (ktruio != NULL) {
608 		ktruio->uio_resid = cnt;
609 		ktrgenio(fd, UIO_WRITE, ktruio, error);
610 	}
611 #endif
612 	td->td_retval[0] = cnt;
613 	return (error);
614 }
615 
616 /*
617  * Truncate a file given a file descriptor.
618  *
619  * Can't use fget_write() here, since must return EINVAL and not EBADF if the
620  * descriptor isn't writable.
621  */
622 int
623 kern_ftruncate(td, fd, length)
624 	struct thread *td;
625 	int fd;
626 	off_t length;
627 {
628 	struct file *fp;
629 	cap_rights_t rights;
630 	int error;
631 
632 	AUDIT_ARG_FD(fd);
633 	if (length < 0)
634 		return (EINVAL);
635 	error = fget(td, fd, cap_rights_init(&rights, CAP_FTRUNCATE), &fp);
636 	if (error)
637 		return (error);
638 	AUDIT_ARG_FILE(td->td_proc, fp);
639 	if (!(fp->f_flag & FWRITE)) {
640 		fdrop(fp, td);
641 		return (EINVAL);
642 	}
643 	error = fo_truncate(fp, length, td->td_ucred, td);
644 	fdrop(fp, td);
645 	return (error);
646 }
647 
648 #ifndef _SYS_SYSPROTO_H_
649 struct ftruncate_args {
650 	int	fd;
651 	int	pad;
652 	off_t	length;
653 };
654 #endif
655 int
656 sys_ftruncate(td, uap)
657 	struct thread *td;
658 	struct ftruncate_args *uap;
659 {
660 
661 	return (kern_ftruncate(td, uap->fd, uap->length));
662 }
663 
664 #if defined(COMPAT_43)
665 #ifndef _SYS_SYSPROTO_H_
666 struct oftruncate_args {
667 	int	fd;
668 	long	length;
669 };
670 #endif
671 int
672 oftruncate(td, uap)
673 	struct thread *td;
674 	struct oftruncate_args *uap;
675 {
676 
677 	return (kern_ftruncate(td, uap->fd, uap->length));
678 }
679 #endif /* COMPAT_43 */
680 
681 #ifndef _SYS_SYSPROTO_H_
682 struct ioctl_args {
683 	int	fd;
684 	u_long	com;
685 	caddr_t	data;
686 };
687 #endif
688 /* ARGSUSED */
689 int
690 sys_ioctl(struct thread *td, struct ioctl_args *uap)
691 {
692 	u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN);
693 	u_long com;
694 	int arg, error;
695 	u_int size;
696 	caddr_t data;
697 
698 	if (uap->com > 0xffffffff) {
699 		printf(
700 		    "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
701 		    td->td_proc->p_pid, td->td_name, uap->com);
702 		uap->com &= 0xffffffff;
703 	}
704 	com = uap->com;
705 
706 	/*
707 	 * Interpret high order word to find amount of data to be
708 	 * copied to/from the user's address space.
709 	 */
710 	size = IOCPARM_LEN(com);
711 	if ((size > IOCPARM_MAX) ||
712 	    ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
713 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
714 	    ((com & IOC_OUT) && size == 0) ||
715 #else
716 	    ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
717 #endif
718 	    ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
719 		return (ENOTTY);
720 
721 	if (size > 0) {
722 		if (com & IOC_VOID) {
723 			/* Integer argument. */
724 			arg = (intptr_t)uap->data;
725 			data = (void *)&arg;
726 			size = 0;
727 		} else {
728 			if (size > SYS_IOCTL_SMALL_SIZE)
729 				data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
730 			else
731 				data = smalldata;
732 		}
733 	} else
734 		data = (void *)&uap->data;
735 	if (com & IOC_IN) {
736 		error = copyin(uap->data, data, (u_int)size);
737 		if (error != 0)
738 			goto out;
739 	} else if (com & IOC_OUT) {
740 		/*
741 		 * Zero the buffer so the user always
742 		 * gets back something deterministic.
743 		 */
744 		bzero(data, size);
745 	}
746 
747 	error = kern_ioctl(td, uap->fd, com, data);
748 
749 	if (error == 0 && (com & IOC_OUT))
750 		error = copyout(data, uap->data, (u_int)size);
751 
752 out:
753 	if (size > SYS_IOCTL_SMALL_SIZE)
754 		free(data, M_IOCTLOPS);
755 	return (error);
756 }
757 
758 int
759 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
760 {
761 	struct file *fp;
762 	struct filedesc *fdp;
763 #ifndef CAPABILITIES
764 	cap_rights_t rights;
765 #endif
766 	int error, tmp, locked;
767 
768 	AUDIT_ARG_FD(fd);
769 	AUDIT_ARG_CMD(com);
770 
771 	fdp = td->td_proc->p_fd;
772 
773 	switch (com) {
774 	case FIONCLEX:
775 	case FIOCLEX:
776 		FILEDESC_XLOCK(fdp);
777 		locked = LA_XLOCKED;
778 		break;
779 	default:
780 #ifdef CAPABILITIES
781 		FILEDESC_SLOCK(fdp);
782 		locked = LA_SLOCKED;
783 #else
784 		locked = LA_UNLOCKED;
785 #endif
786 		break;
787 	}
788 
789 #ifdef CAPABILITIES
790 	if ((fp = fget_locked(fdp, fd)) == NULL) {
791 		error = EBADF;
792 		goto out;
793 	}
794 	if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
795 		fp = NULL;	/* fhold() was not called yet */
796 		goto out;
797 	}
798 	fhold(fp);
799 	if (locked == LA_SLOCKED) {
800 		FILEDESC_SUNLOCK(fdp);
801 		locked = LA_UNLOCKED;
802 	}
803 #else
804 	error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
805 	if (error != 0) {
806 		fp = NULL;
807 		goto out;
808 	}
809 #endif
810 	if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
811 		error = EBADF;
812 		goto out;
813 	}
814 
815 	switch (com) {
816 	case FIONCLEX:
817 		fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
818 		goto out;
819 	case FIOCLEX:
820 		fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
821 		goto out;
822 	case FIONBIO:
823 		if ((tmp = *(int *)data))
824 			atomic_set_int(&fp->f_flag, FNONBLOCK);
825 		else
826 			atomic_clear_int(&fp->f_flag, FNONBLOCK);
827 		data = (void *)&tmp;
828 		break;
829 	case FIOASYNC:
830 		if ((tmp = *(int *)data))
831 			atomic_set_int(&fp->f_flag, FASYNC);
832 		else
833 			atomic_clear_int(&fp->f_flag, FASYNC);
834 		data = (void *)&tmp;
835 		break;
836 	}
837 
838 	error = fo_ioctl(fp, com, data, td->td_ucred, td);
839 out:
840 	switch (locked) {
841 	case LA_XLOCKED:
842 		FILEDESC_XUNLOCK(fdp);
843 		break;
844 #ifdef CAPABILITIES
845 	case LA_SLOCKED:
846 		FILEDESC_SUNLOCK(fdp);
847 		break;
848 #endif
849 	default:
850 		FILEDESC_UNLOCK_ASSERT(fdp);
851 		break;
852 	}
853 	if (fp != NULL)
854 		fdrop(fp, td);
855 	return (error);
856 }
857 
858 int
859 poll_no_poll(int events)
860 {
861 	/*
862 	 * Return true for read/write.  If the user asked for something
863 	 * special, return POLLNVAL, so that clients have a way of
864 	 * determining reliably whether or not the extended
865 	 * functionality is present without hard-coding knowledge
866 	 * of specific filesystem implementations.
867 	 */
868 	if (events & ~POLLSTANDARD)
869 		return (POLLNVAL);
870 
871 	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
872 }
873 
874 int
875 sys_pselect(struct thread *td, struct pselect_args *uap)
876 {
877 	struct timespec ts;
878 	struct timeval tv, *tvp;
879 	sigset_t set, *uset;
880 	int error;
881 
882 	if (uap->ts != NULL) {
883 		error = copyin(uap->ts, &ts, sizeof(ts));
884 		if (error != 0)
885 		    return (error);
886 		TIMESPEC_TO_TIMEVAL(&tv, &ts);
887 		tvp = &tv;
888 	} else
889 		tvp = NULL;
890 	if (uap->sm != NULL) {
891 		error = copyin(uap->sm, &set, sizeof(set));
892 		if (error != 0)
893 			return (error);
894 		uset = &set;
895 	} else
896 		uset = NULL;
897 	return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
898 	    uset, NFDBITS));
899 }
900 
901 int
902 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
903     struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
904 {
905 	int error;
906 
907 	if (uset != NULL) {
908 		error = kern_sigprocmask(td, SIG_SETMASK, uset,
909 		    &td->td_oldsigmask, 0);
910 		if (error != 0)
911 			return (error);
912 		td->td_pflags |= TDP_OLDMASK;
913 		/*
914 		 * Make sure that ast() is called on return to
915 		 * usermode and TDP_OLDMASK is cleared, restoring old
916 		 * sigmask.
917 		 */
918 		thread_lock(td);
919 		td->td_flags |= TDF_ASTPENDING;
920 		thread_unlock(td);
921 	}
922 	error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
923 	return (error);
924 }
925 
926 #ifndef _SYS_SYSPROTO_H_
927 struct select_args {
928 	int	nd;
929 	fd_set	*in, *ou, *ex;
930 	struct	timeval *tv;
931 };
932 #endif
933 int
934 sys_select(struct thread *td, struct select_args *uap)
935 {
936 	struct timeval tv, *tvp;
937 	int error;
938 
939 	if (uap->tv != NULL) {
940 		error = copyin(uap->tv, &tv, sizeof(tv));
941 		if (error)
942 			return (error);
943 		tvp = &tv;
944 	} else
945 		tvp = NULL;
946 
947 	return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
948 	    NFDBITS));
949 }
950 
951 /*
952  * In the unlikely case when user specified n greater then the last
953  * open file descriptor, check that no bits are set after the last
954  * valid fd.  We must return EBADF if any is set.
955  *
956  * There are applications that rely on the behaviour.
957  *
958  * nd is fd_lastfile + 1.
959  */
960 static int
961 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
962 {
963 	char *addr, *oaddr;
964 	int b, i, res;
965 	uint8_t bits;
966 
967 	if (nd >= ndu || fd_in == NULL)
968 		return (0);
969 
970 	oaddr = NULL;
971 	bits = 0; /* silence gcc */
972 	for (i = nd; i < ndu; i++) {
973 		b = i / NBBY;
974 #if BYTE_ORDER == LITTLE_ENDIAN
975 		addr = (char *)fd_in + b;
976 #else
977 		addr = (char *)fd_in;
978 		if (abi_nfdbits == NFDBITS) {
979 			addr += rounddown(b, sizeof(fd_mask)) +
980 			    sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
981 		} else {
982 			addr += rounddown(b, sizeof(uint32_t)) +
983 			    sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
984 		}
985 #endif
986 		if (addr != oaddr) {
987 			res = fubyte(addr);
988 			if (res == -1)
989 				return (EFAULT);
990 			oaddr = addr;
991 			bits = res;
992 		}
993 		if ((bits & (1 << (i % NBBY))) != 0)
994 			return (EBADF);
995 	}
996 	return (0);
997 }
998 
999 int
1000 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
1001     fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
1002 {
1003 	struct filedesc *fdp;
1004 	/*
1005 	 * The magic 2048 here is chosen to be just enough for FD_SETSIZE
1006 	 * infds with the new FD_SETSIZE of 1024, and more than enough for
1007 	 * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
1008 	 * of 256.
1009 	 */
1010 	fd_mask s_selbits[howmany(2048, NFDBITS)];
1011 	fd_mask *ibits[3], *obits[3], *selbits, *sbp;
1012 	struct timeval rtv;
1013 	sbintime_t asbt, precision, rsbt;
1014 	u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
1015 	int error, lf, ndu;
1016 
1017 	if (nd < 0)
1018 		return (EINVAL);
1019 	fdp = td->td_proc->p_fd;
1020 	ndu = nd;
1021 	lf = fdp->fd_lastfile;
1022 	if (nd > lf + 1)
1023 		nd = lf + 1;
1024 
1025 	error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
1026 	if (error != 0)
1027 		return (error);
1028 	error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
1029 	if (error != 0)
1030 		return (error);
1031 	error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
1032 	if (error != 0)
1033 		return (error);
1034 
1035 	/*
1036 	 * Allocate just enough bits for the non-null fd_sets.  Use the
1037 	 * preallocated auto buffer if possible.
1038 	 */
1039 	nfdbits = roundup(nd, NFDBITS);
1040 	ncpbytes = nfdbits / NBBY;
1041 	ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
1042 	nbufbytes = 0;
1043 	if (fd_in != NULL)
1044 		nbufbytes += 2 * ncpbytes;
1045 	if (fd_ou != NULL)
1046 		nbufbytes += 2 * ncpbytes;
1047 	if (fd_ex != NULL)
1048 		nbufbytes += 2 * ncpbytes;
1049 	if (nbufbytes <= sizeof s_selbits)
1050 		selbits = &s_selbits[0];
1051 	else
1052 		selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
1053 
1054 	/*
1055 	 * Assign pointers into the bit buffers and fetch the input bits.
1056 	 * Put the output buffers together so that they can be bzeroed
1057 	 * together.
1058 	 */
1059 	sbp = selbits;
1060 #define	getbits(name, x) \
1061 	do {								\
1062 		if (name == NULL) {					\
1063 			ibits[x] = NULL;				\
1064 			obits[x] = NULL;				\
1065 		} else {						\
1066 			ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp;	\
1067 			obits[x] = sbp;					\
1068 			sbp += ncpbytes / sizeof *sbp;			\
1069 			error = copyin(name, ibits[x], ncpubytes);	\
1070 			if (error != 0)					\
1071 				goto done;				\
1072 			bzero((char *)ibits[x] + ncpubytes,		\
1073 			    ncpbytes - ncpubytes);			\
1074 		}							\
1075 	} while (0)
1076 	getbits(fd_in, 0);
1077 	getbits(fd_ou, 1);
1078 	getbits(fd_ex, 2);
1079 #undef	getbits
1080 
1081 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
1082 	/*
1083 	 * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
1084 	 * we are running under 32-bit emulation. This should be more
1085 	 * generic.
1086 	 */
1087 #define swizzle_fdset(bits)						\
1088 	if (abi_nfdbits != NFDBITS && bits != NULL) {			\
1089 		int i;							\
1090 		for (i = 0; i < ncpbytes / sizeof *sbp; i++)		\
1091 			bits[i] = (bits[i] >> 32) | (bits[i] << 32);	\
1092 	}
1093 #else
1094 #define swizzle_fdset(bits)
1095 #endif
1096 
1097 	/* Make sure the bit order makes it through an ABI transition */
1098 	swizzle_fdset(ibits[0]);
1099 	swizzle_fdset(ibits[1]);
1100 	swizzle_fdset(ibits[2]);
1101 
1102 	if (nbufbytes != 0)
1103 		bzero(selbits, nbufbytes / 2);
1104 
1105 	precision = 0;
1106 	if (tvp != NULL) {
1107 		rtv = *tvp;
1108 		if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
1109 		    rtv.tv_usec >= 1000000) {
1110 			error = EINVAL;
1111 			goto done;
1112 		}
1113 		if (!timevalisset(&rtv))
1114 			asbt = 0;
1115 		else if (rtv.tv_sec <= INT32_MAX) {
1116 			rsbt = tvtosbt(rtv);
1117 			precision = rsbt;
1118 			precision >>= tc_precexp;
1119 			if (TIMESEL(&asbt, rsbt))
1120 				asbt += tc_tick_sbt;
1121 			if (asbt <= SBT_MAX - rsbt)
1122 				asbt += rsbt;
1123 			else
1124 				asbt = -1;
1125 		} else
1126 			asbt = -1;
1127 	} else
1128 		asbt = -1;
1129 	seltdinit(td);
1130 	/* Iterate until the timeout expires or descriptors become ready. */
1131 	for (;;) {
1132 		error = selscan(td, ibits, obits, nd);
1133 		if (error || td->td_retval[0] != 0)
1134 			break;
1135 		error = seltdwait(td, asbt, precision);
1136 		if (error)
1137 			break;
1138 		error = selrescan(td, ibits, obits);
1139 		if (error || td->td_retval[0] != 0)
1140 			break;
1141 	}
1142 	seltdclear(td);
1143 
1144 done:
1145 	/* select is not restarted after signals... */
1146 	if (error == ERESTART)
1147 		error = EINTR;
1148 	if (error == EWOULDBLOCK)
1149 		error = 0;
1150 
1151 	/* swizzle bit order back, if necessary */
1152 	swizzle_fdset(obits[0]);
1153 	swizzle_fdset(obits[1]);
1154 	swizzle_fdset(obits[2]);
1155 #undef swizzle_fdset
1156 
1157 #define	putbits(name, x) \
1158 	if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
1159 		error = error2;
1160 	if (error == 0) {
1161 		int error2;
1162 
1163 		putbits(fd_in, 0);
1164 		putbits(fd_ou, 1);
1165 		putbits(fd_ex, 2);
1166 #undef putbits
1167 	}
1168 	if (selbits != &s_selbits[0])
1169 		free(selbits, M_SELECT);
1170 
1171 	return (error);
1172 }
1173 /*
1174  * Convert a select bit set to poll flags.
1175  *
1176  * The backend always returns POLLHUP/POLLERR if appropriate and we
1177  * return this as a set bit in any set.
1178  */
1179 static int select_flags[3] = {
1180     POLLRDNORM | POLLHUP | POLLERR,
1181     POLLWRNORM | POLLHUP | POLLERR,
1182     POLLRDBAND | POLLERR
1183 };
1184 
1185 /*
1186  * Compute the fo_poll flags required for a fd given by the index and
1187  * bit position in the fd_mask array.
1188  */
1189 static __inline int
1190 selflags(fd_mask **ibits, int idx, fd_mask bit)
1191 {
1192 	int flags;
1193 	int msk;
1194 
1195 	flags = 0;
1196 	for (msk = 0; msk < 3; msk++) {
1197 		if (ibits[msk] == NULL)
1198 			continue;
1199 		if ((ibits[msk][idx] & bit) == 0)
1200 			continue;
1201 		flags |= select_flags[msk];
1202 	}
1203 	return (flags);
1204 }
1205 
1206 /*
1207  * Set the appropriate output bits given a mask of fired events and the
1208  * input bits originally requested.
1209  */
1210 static __inline int
1211 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
1212 {
1213 	int msk;
1214 	int n;
1215 
1216 	n = 0;
1217 	for (msk = 0; msk < 3; msk++) {
1218 		if ((events & select_flags[msk]) == 0)
1219 			continue;
1220 		if (ibits[msk] == NULL)
1221 			continue;
1222 		if ((ibits[msk][idx] & bit) == 0)
1223 			continue;
1224 		/*
1225 		 * XXX Check for a duplicate set.  This can occur because a
1226 		 * socket calls selrecord() twice for each poll() call
1227 		 * resulting in two selfds per real fd.  selrescan() will
1228 		 * call selsetbits twice as a result.
1229 		 */
1230 		if ((obits[msk][idx] & bit) != 0)
1231 			continue;
1232 		obits[msk][idx] |= bit;
1233 		n++;
1234 	}
1235 
1236 	return (n);
1237 }
1238 
1239 static __inline int
1240 getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
1241 {
1242 	cap_rights_t rights;
1243 
1244 	cap_rights_init(&rights, CAP_EVENT);
1245 
1246 	return (fget_unlocked(fdp, fd, &rights, fpp, NULL));
1247 }
1248 
1249 /*
1250  * Traverse the list of fds attached to this thread's seltd and check for
1251  * completion.
1252  */
1253 static int
1254 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
1255 {
1256 	struct filedesc *fdp;
1257 	struct selinfo *si;
1258 	struct seltd *stp;
1259 	struct selfd *sfp;
1260 	struct selfd *sfn;
1261 	struct file *fp;
1262 	fd_mask bit;
1263 	int fd, ev, n, idx;
1264 	int error;
1265 
1266 	fdp = td->td_proc->p_fd;
1267 	stp = td->td_sel;
1268 	n = 0;
1269 	STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
1270 		fd = (int)(uintptr_t)sfp->sf_cookie;
1271 		si = sfp->sf_si;
1272 		selfdfree(stp, sfp);
1273 		/* If the selinfo wasn't cleared the event didn't fire. */
1274 		if (si != NULL)
1275 			continue;
1276 		error = getselfd_cap(fdp, fd, &fp);
1277 		if (error)
1278 			return (error);
1279 		idx = fd / NFDBITS;
1280 		bit = (fd_mask)1 << (fd % NFDBITS);
1281 		ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
1282 		fdrop(fp, td);
1283 		if (ev != 0)
1284 			n += selsetbits(ibits, obits, idx, bit, ev);
1285 	}
1286 	stp->st_flags = 0;
1287 	td->td_retval[0] = n;
1288 	return (0);
1289 }
1290 
1291 /*
1292  * Perform the initial filedescriptor scan and register ourselves with
1293  * each selinfo.
1294  */
1295 static int
1296 selscan(td, ibits, obits, nfd)
1297 	struct thread *td;
1298 	fd_mask **ibits, **obits;
1299 	int nfd;
1300 {
1301 	struct filedesc *fdp;
1302 	struct file *fp;
1303 	fd_mask bit;
1304 	int ev, flags, end, fd;
1305 	int n, idx;
1306 	int error;
1307 
1308 	fdp = td->td_proc->p_fd;
1309 	n = 0;
1310 	for (idx = 0, fd = 0; fd < nfd; idx++) {
1311 		end = imin(fd + NFDBITS, nfd);
1312 		for (bit = 1; fd < end; bit <<= 1, fd++) {
1313 			/* Compute the list of events we're interested in. */
1314 			flags = selflags(ibits, idx, bit);
1315 			if (flags == 0)
1316 				continue;
1317 			error = getselfd_cap(fdp, fd, &fp);
1318 			if (error)
1319 				return (error);
1320 			selfdalloc(td, (void *)(uintptr_t)fd);
1321 			ev = fo_poll(fp, flags, td->td_ucred, td);
1322 			fdrop(fp, td);
1323 			if (ev != 0)
1324 				n += selsetbits(ibits, obits, idx, bit, ev);
1325 		}
1326 	}
1327 
1328 	td->td_retval[0] = n;
1329 	return (0);
1330 }
1331 
1332 int
1333 sys_poll(struct thread *td, struct poll_args *uap)
1334 {
1335 	struct timespec ts, *tsp;
1336 
1337 	if (uap->timeout != INFTIM) {
1338 		if (uap->timeout < 0)
1339 			return (EINVAL);
1340 		ts.tv_sec = uap->timeout / 1000;
1341 		ts.tv_nsec = (uap->timeout % 1000) * 1000000;
1342 		tsp = &ts;
1343 	} else
1344 		tsp = NULL;
1345 
1346 	return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
1347 }
1348 
1349 int
1350 kern_poll(struct thread *td, struct pollfd *fds, u_int nfds,
1351     struct timespec *tsp, sigset_t *uset)
1352 {
1353 	struct pollfd *bits;
1354 	struct pollfd smallbits[32];
1355 	sbintime_t sbt, precision, tmp;
1356 	time_t over;
1357 	struct timespec ts;
1358 	int error;
1359 	size_t ni;
1360 
1361 	precision = 0;
1362 	if (tsp != NULL) {
1363 		if (tsp->tv_sec < 0)
1364 			return (EINVAL);
1365 		if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
1366 			return (EINVAL);
1367 		if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
1368 			sbt = 0;
1369 		else {
1370 			ts = *tsp;
1371 			if (ts.tv_sec > INT32_MAX / 2) {
1372 				over = ts.tv_sec - INT32_MAX / 2;
1373 				ts.tv_sec -= over;
1374 			} else
1375 				over = 0;
1376 			tmp = tstosbt(ts);
1377 			precision = tmp;
1378 			precision >>= tc_precexp;
1379 			if (TIMESEL(&sbt, tmp))
1380 				sbt += tc_tick_sbt;
1381 			sbt += tmp;
1382 		}
1383 	} else
1384 		sbt = -1;
1385 
1386 	if (nfds > maxfilesperproc && nfds > FD_SETSIZE)
1387 		return (EINVAL);
1388 	ni = nfds * sizeof(struct pollfd);
1389 	if (ni > sizeof(smallbits))
1390 		bits = malloc(ni, M_TEMP, M_WAITOK);
1391 	else
1392 		bits = smallbits;
1393 	error = copyin(fds, bits, ni);
1394 	if (error)
1395 		goto done;
1396 
1397 	if (uset != NULL) {
1398 		error = kern_sigprocmask(td, SIG_SETMASK, uset,
1399 		    &td->td_oldsigmask, 0);
1400 		if (error)
1401 			goto done;
1402 		td->td_pflags |= TDP_OLDMASK;
1403 		/*
1404 		 * Make sure that ast() is called on return to
1405 		 * usermode and TDP_OLDMASK is cleared, restoring old
1406 		 * sigmask.
1407 		 */
1408 		thread_lock(td);
1409 		td->td_flags |= TDF_ASTPENDING;
1410 		thread_unlock(td);
1411 	}
1412 
1413 	seltdinit(td);
1414 	/* Iterate until the timeout expires or descriptors become ready. */
1415 	for (;;) {
1416 		error = pollscan(td, bits, nfds);
1417 		if (error || td->td_retval[0] != 0)
1418 			break;
1419 		error = seltdwait(td, sbt, precision);
1420 		if (error)
1421 			break;
1422 		error = pollrescan(td);
1423 		if (error || td->td_retval[0] != 0)
1424 			break;
1425 	}
1426 	seltdclear(td);
1427 
1428 done:
1429 	/* poll is not restarted after signals... */
1430 	if (error == ERESTART)
1431 		error = EINTR;
1432 	if (error == EWOULDBLOCK)
1433 		error = 0;
1434 	if (error == 0) {
1435 		error = pollout(td, bits, fds, nfds);
1436 		if (error)
1437 			goto out;
1438 	}
1439 out:
1440 	if (ni > sizeof(smallbits))
1441 		free(bits, M_TEMP);
1442 	return (error);
1443 }
1444 
1445 int
1446 sys_ppoll(struct thread *td, struct ppoll_args *uap)
1447 {
1448 	struct timespec ts, *tsp;
1449 	sigset_t set, *ssp;
1450 	int error;
1451 
1452 	if (uap->ts != NULL) {
1453 		error = copyin(uap->ts, &ts, sizeof(ts));
1454 		if (error)
1455 			return (error);
1456 		tsp = &ts;
1457 	} else
1458 		tsp = NULL;
1459 	if (uap->set != NULL) {
1460 		error = copyin(uap->set, &set, sizeof(set));
1461 		if (error)
1462 			return (error);
1463 		ssp = &set;
1464 	} else
1465 		ssp = NULL;
1466 	/*
1467 	 * fds is still a pointer to user space. kern_poll() will
1468 	 * take care of copyin that array to the kernel space.
1469 	 */
1470 
1471 	return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
1472 }
1473 
1474 static int
1475 pollrescan(struct thread *td)
1476 {
1477 	struct seltd *stp;
1478 	struct selfd *sfp;
1479 	struct selfd *sfn;
1480 	struct selinfo *si;
1481 	struct filedesc *fdp;
1482 	struct file *fp;
1483 	struct pollfd *fd;
1484 #ifdef CAPABILITIES
1485 	cap_rights_t rights;
1486 #endif
1487 	int n;
1488 
1489 	n = 0;
1490 	fdp = td->td_proc->p_fd;
1491 	stp = td->td_sel;
1492 	FILEDESC_SLOCK(fdp);
1493 	STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
1494 		fd = (struct pollfd *)sfp->sf_cookie;
1495 		si = sfp->sf_si;
1496 		selfdfree(stp, sfp);
1497 		/* If the selinfo wasn't cleared the event didn't fire. */
1498 		if (si != NULL)
1499 			continue;
1500 		fp = fdp->fd_ofiles[fd->fd].fde_file;
1501 #ifdef CAPABILITIES
1502 		if (fp == NULL ||
1503 		    cap_check(cap_rights(fdp, fd->fd),
1504 		    cap_rights_init(&rights, CAP_EVENT)) != 0)
1505 #else
1506 		if (fp == NULL)
1507 #endif
1508 		{
1509 			fd->revents = POLLNVAL;
1510 			n++;
1511 			continue;
1512 		}
1513 
1514 		/*
1515 		 * Note: backend also returns POLLHUP and
1516 		 * POLLERR if appropriate.
1517 		 */
1518 		fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
1519 		if (fd->revents != 0)
1520 			n++;
1521 	}
1522 	FILEDESC_SUNLOCK(fdp);
1523 	stp->st_flags = 0;
1524 	td->td_retval[0] = n;
1525 	return (0);
1526 }
1527 
1528 
1529 static int
1530 pollout(td, fds, ufds, nfd)
1531 	struct thread *td;
1532 	struct pollfd *fds;
1533 	struct pollfd *ufds;
1534 	u_int nfd;
1535 {
1536 	int error = 0;
1537 	u_int i = 0;
1538 	u_int n = 0;
1539 
1540 	for (i = 0; i < nfd; i++) {
1541 		error = copyout(&fds->revents, &ufds->revents,
1542 		    sizeof(ufds->revents));
1543 		if (error)
1544 			return (error);
1545 		if (fds->revents != 0)
1546 			n++;
1547 		fds++;
1548 		ufds++;
1549 	}
1550 	td->td_retval[0] = n;
1551 	return (0);
1552 }
1553 
1554 static int
1555 pollscan(td, fds, nfd)
1556 	struct thread *td;
1557 	struct pollfd *fds;
1558 	u_int nfd;
1559 {
1560 	struct filedesc *fdp = td->td_proc->p_fd;
1561 	struct file *fp;
1562 #ifdef CAPABILITIES
1563 	cap_rights_t rights;
1564 #endif
1565 	int i, n = 0;
1566 
1567 	FILEDESC_SLOCK(fdp);
1568 	for (i = 0; i < nfd; i++, fds++) {
1569 		if (fds->fd > fdp->fd_lastfile) {
1570 			fds->revents = POLLNVAL;
1571 			n++;
1572 		} else if (fds->fd < 0) {
1573 			fds->revents = 0;
1574 		} else {
1575 			fp = fdp->fd_ofiles[fds->fd].fde_file;
1576 #ifdef CAPABILITIES
1577 			if (fp == NULL ||
1578 			    cap_check(cap_rights(fdp, fds->fd),
1579 			    cap_rights_init(&rights, CAP_EVENT)) != 0)
1580 #else
1581 			if (fp == NULL)
1582 #endif
1583 			{
1584 				fds->revents = POLLNVAL;
1585 				n++;
1586 			} else {
1587 				/*
1588 				 * Note: backend also returns POLLHUP and
1589 				 * POLLERR if appropriate.
1590 				 */
1591 				selfdalloc(td, fds);
1592 				fds->revents = fo_poll(fp, fds->events,
1593 				    td->td_ucred, td);
1594 				/*
1595 				 * POSIX requires POLLOUT to be never
1596 				 * set simultaneously with POLLHUP.
1597 				 */
1598 				if ((fds->revents & POLLHUP) != 0)
1599 					fds->revents &= ~POLLOUT;
1600 
1601 				if (fds->revents != 0)
1602 					n++;
1603 			}
1604 		}
1605 	}
1606 	FILEDESC_SUNLOCK(fdp);
1607 	td->td_retval[0] = n;
1608 	return (0);
1609 }
1610 
1611 /*
1612  * XXX This was created specifically to support netncp and netsmb.  This
1613  * allows the caller to specify a socket to wait for events on.  It returns
1614  * 0 if any events matched and an error otherwise.  There is no way to
1615  * determine which events fired.
1616  */
1617 int
1618 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
1619 {
1620 	struct timeval rtv;
1621 	sbintime_t asbt, precision, rsbt;
1622 	int error;
1623 
1624 	precision = 0;	/* stupid gcc! */
1625 	if (tvp != NULL) {
1626 		rtv = *tvp;
1627 		if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
1628 		    rtv.tv_usec >= 1000000)
1629 			return (EINVAL);
1630 		if (!timevalisset(&rtv))
1631 			asbt = 0;
1632 		else if (rtv.tv_sec <= INT32_MAX) {
1633 			rsbt = tvtosbt(rtv);
1634 			precision = rsbt;
1635 			precision >>= tc_precexp;
1636 			if (TIMESEL(&asbt, rsbt))
1637 				asbt += tc_tick_sbt;
1638 			if (asbt <= SBT_MAX - rsbt)
1639 				asbt += rsbt;
1640 			else
1641 				asbt = -1;
1642 		} else
1643 			asbt = -1;
1644 	} else
1645 		asbt = -1;
1646 	seltdinit(td);
1647 	/*
1648 	 * Iterate until the timeout expires or the socket becomes ready.
1649 	 */
1650 	for (;;) {
1651 		selfdalloc(td, NULL);
1652 		error = sopoll(so, events, NULL, td);
1653 		/* error here is actually the ready events. */
1654 		if (error)
1655 			return (0);
1656 		error = seltdwait(td, asbt, precision);
1657 		if (error)
1658 			break;
1659 	}
1660 	seltdclear(td);
1661 	/* XXX Duplicates ncp/smb behavior. */
1662 	if (error == ERESTART)
1663 		error = 0;
1664 	return (error);
1665 }
1666 
1667 /*
1668  * Preallocate two selfds associated with 'cookie'.  Some fo_poll routines
1669  * have two select sets, one for read and another for write.
1670  */
1671 static void
1672 selfdalloc(struct thread *td, void *cookie)
1673 {
1674 	struct seltd *stp;
1675 
1676 	stp = td->td_sel;
1677 	if (stp->st_free1 == NULL)
1678 		stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
1679 	stp->st_free1->sf_td = stp;
1680 	stp->st_free1->sf_cookie = cookie;
1681 	if (stp->st_free2 == NULL)
1682 		stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
1683 	stp->st_free2->sf_td = stp;
1684 	stp->st_free2->sf_cookie = cookie;
1685 }
1686 
1687 static void
1688 selfdfree(struct seltd *stp, struct selfd *sfp)
1689 {
1690 	STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
1691 	if (sfp->sf_si != NULL) {
1692 		mtx_lock(sfp->sf_mtx);
1693 		if (sfp->sf_si != NULL) {
1694 			TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
1695 			refcount_release(&sfp->sf_refs);
1696 		}
1697 		mtx_unlock(sfp->sf_mtx);
1698 	}
1699 	if (refcount_release(&sfp->sf_refs))
1700 		uma_zfree(selfd_zone, sfp);
1701 }
1702 
1703 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
1704 void
1705 seldrain(sip)
1706         struct selinfo *sip;
1707 {
1708 
1709 	/*
1710 	 * This feature is already provided by doselwakeup(), thus it is
1711 	 * enough to go for it.
1712 	 * Eventually, the context, should take care to avoid races
1713 	 * between thread calling select()/poll() and file descriptor
1714 	 * detaching, but, again, the races are just the same as
1715 	 * selwakeup().
1716 	 */
1717         doselwakeup(sip, -1);
1718 }
1719 
1720 /*
1721  * Record a select request.
1722  */
1723 void
1724 selrecord(selector, sip)
1725 	struct thread *selector;
1726 	struct selinfo *sip;
1727 {
1728 	struct selfd *sfp;
1729 	struct seltd *stp;
1730 	struct mtx *mtxp;
1731 
1732 	stp = selector->td_sel;
1733 	/*
1734 	 * Don't record when doing a rescan.
1735 	 */
1736 	if (stp->st_flags & SELTD_RESCAN)
1737 		return;
1738 	/*
1739 	 * Grab one of the preallocated descriptors.
1740 	 */
1741 	sfp = NULL;
1742 	if ((sfp = stp->st_free1) != NULL)
1743 		stp->st_free1 = NULL;
1744 	else if ((sfp = stp->st_free2) != NULL)
1745 		stp->st_free2 = NULL;
1746 	else
1747 		panic("selrecord: No free selfd on selq");
1748 	mtxp = sip->si_mtx;
1749 	if (mtxp == NULL)
1750 		mtxp = mtx_pool_find(mtxpool_select, sip);
1751 	/*
1752 	 * Initialize the sfp and queue it in the thread.
1753 	 */
1754 	sfp->sf_si = sip;
1755 	sfp->sf_mtx = mtxp;
1756 	refcount_init(&sfp->sf_refs, 2);
1757 	STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
1758 	/*
1759 	 * Now that we've locked the sip, check for initialization.
1760 	 */
1761 	mtx_lock(mtxp);
1762 	if (sip->si_mtx == NULL) {
1763 		sip->si_mtx = mtxp;
1764 		TAILQ_INIT(&sip->si_tdlist);
1765 	}
1766 	/*
1767 	 * Add this thread to the list of selfds listening on this selinfo.
1768 	 */
1769 	TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
1770 	mtx_unlock(sip->si_mtx);
1771 }
1772 
1773 /* Wake up a selecting thread. */
1774 void
1775 selwakeup(sip)
1776 	struct selinfo *sip;
1777 {
1778 	doselwakeup(sip, -1);
1779 }
1780 
1781 /* Wake up a selecting thread, and set its priority. */
1782 void
1783 selwakeuppri(sip, pri)
1784 	struct selinfo *sip;
1785 	int pri;
1786 {
1787 	doselwakeup(sip, pri);
1788 }
1789 
1790 /*
1791  * Do a wakeup when a selectable event occurs.
1792  */
1793 static void
1794 doselwakeup(sip, pri)
1795 	struct selinfo *sip;
1796 	int pri;
1797 {
1798 	struct selfd *sfp;
1799 	struct selfd *sfn;
1800 	struct seltd *stp;
1801 
1802 	/* If it's not initialized there can't be any waiters. */
1803 	if (sip->si_mtx == NULL)
1804 		return;
1805 	/*
1806 	 * Locking the selinfo locks all selfds associated with it.
1807 	 */
1808 	mtx_lock(sip->si_mtx);
1809 	TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
1810 		/*
1811 		 * Once we remove this sfp from the list and clear the
1812 		 * sf_si seltdclear will know to ignore this si.
1813 		 */
1814 		TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
1815 		sfp->sf_si = NULL;
1816 		stp = sfp->sf_td;
1817 		mtx_lock(&stp->st_mtx);
1818 		stp->st_flags |= SELTD_PENDING;
1819 		cv_broadcastpri(&stp->st_wait, pri);
1820 		mtx_unlock(&stp->st_mtx);
1821 		if (refcount_release(&sfp->sf_refs))
1822 			uma_zfree(selfd_zone, sfp);
1823 	}
1824 	mtx_unlock(sip->si_mtx);
1825 }
1826 
1827 static void
1828 seltdinit(struct thread *td)
1829 {
1830 	struct seltd *stp;
1831 
1832 	if ((stp = td->td_sel) != NULL)
1833 		goto out;
1834 	td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
1835 	mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
1836 	cv_init(&stp->st_wait, "select");
1837 out:
1838 	stp->st_flags = 0;
1839 	STAILQ_INIT(&stp->st_selq);
1840 }
1841 
1842 static int
1843 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
1844 {
1845 	struct seltd *stp;
1846 	int error;
1847 
1848 	stp = td->td_sel;
1849 	/*
1850 	 * An event of interest may occur while we do not hold the seltd
1851 	 * locked so check the pending flag before we sleep.
1852 	 */
1853 	mtx_lock(&stp->st_mtx);
1854 	/*
1855 	 * Any further calls to selrecord will be a rescan.
1856 	 */
1857 	stp->st_flags |= SELTD_RESCAN;
1858 	if (stp->st_flags & SELTD_PENDING) {
1859 		mtx_unlock(&stp->st_mtx);
1860 		return (0);
1861 	}
1862 	if (sbt == 0)
1863 		error = EWOULDBLOCK;
1864 	else if (sbt != -1)
1865 		error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
1866 		    sbt, precision, C_ABSOLUTE);
1867 	else
1868 		error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
1869 	mtx_unlock(&stp->st_mtx);
1870 
1871 	return (error);
1872 }
1873 
1874 void
1875 seltdfini(struct thread *td)
1876 {
1877 	struct seltd *stp;
1878 
1879 	stp = td->td_sel;
1880 	if (stp == NULL)
1881 		return;
1882 	if (stp->st_free1)
1883 		uma_zfree(selfd_zone, stp->st_free1);
1884 	if (stp->st_free2)
1885 		uma_zfree(selfd_zone, stp->st_free2);
1886 	td->td_sel = NULL;
1887 	free(stp, M_SELECT);
1888 }
1889 
1890 /*
1891  * Remove the references to the thread from all of the objects we were
1892  * polling.
1893  */
1894 static void
1895 seltdclear(struct thread *td)
1896 {
1897 	struct seltd *stp;
1898 	struct selfd *sfp;
1899 	struct selfd *sfn;
1900 
1901 	stp = td->td_sel;
1902 	STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
1903 		selfdfree(stp, sfp);
1904 	stp->st_flags = 0;
1905 }
1906 
1907 static void selectinit(void *);
1908 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
1909 static void
1910 selectinit(void *dummy __unused)
1911 {
1912 
1913 	selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
1914 	    NULL, NULL, UMA_ALIGN_PTR, 0);
1915 	mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
1916 }
1917 
1918 /*
1919  * Set up a syscall return value that follows the convention specified for
1920  * posix_* functions.
1921  */
1922 int
1923 kern_posix_error(struct thread *td, int error)
1924 {
1925 
1926 	if (error <= 0)
1927 		return (error);
1928 	td->td_errno = error;
1929 	td->td_pflags |= TDP_NERRNO;
1930 	td->td_retval[0] = error;
1931 	return (0);
1932 }
1933